Rotary hook for sewing machines



Aug. 24, 1943. J. D. -KARLE I ROTARY HOOKS FOR SEWING MACHINES Filed Nov. 5, 1940 gmc/who@ Uz/zn Earle Patented Aug. 24, 1943 ROTARY HOOK FOR SEWING MACHINES John D. Karle, Roselle Park, N. J., assignor to The Singer Manufacturing Company, Eliz beth, N. J., a corporation of N ew Jersey Application November 5, 1940, Serial No. 364,373

3y Claims.

Another object of the invention is to x the portions of the fan-blades which travel at the highest speed to the hook-body so that vibration and hum will be reduced to a minimum.

With the above and other objects on View, as

will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawing vof a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

Fig. 1 is a side elevation of a rotary hook for sewing machines showing my improved fan arrangement embodied therein.

Fig. 2 is a rear elevation of the in Fig. 1.

Fig. 3 is a perspective view of the fan.

Fig. 4 is a perspective view of a modiiied form of fan for the hook shown in Figs. 1 and 2.

In the. embodiment selected for illustration the cup-shaped hook-body comprises the hub I which is adapted to be secured to a rotary shaft I I by the screws I2. The hub is formed with radially extending arms I3 made integral with the hook shown laterally extending arms I4 which carry the rim portion I5 formed with a loop-seizing beak `lli and a loop-controlling tail Il, the rim portion between the beak I6 and tail I'I being cut away to provide a space for entrance of the needlethread. The inner surface of the rim is provided with a raceway I5 in which the usual stationary y thread-case is journaled. The above described hook is fully shown and described in my cepending application Serial No. 269,357, filed Apr. 22, 1939, to which reference may be had for a more detailed description of the hook. l

Fixed to the rim I5 by the screws I8 is a sheetmetal guard-plate I9 formed with laterally extending leg-portions 20 which carry the L-shaped fan-blades 2|. The leg-portions 20 and one limb of the L-shaped fan-blades 2| overlie two of the arms I4 and the free lirnbv of the fan-blade extends into the chamber located at the side of the rim and towards the hub of the hook. To the third arm I4 there is secured by the screw 22 a separate L-shaped fan-blade 23 the free end of which also extends into the chamber and towards the hub of the hook.

In the modiiication illustrated in Fig. 4 the guard-plate 29 is adapted to be secured to the rim I5 of the hook by screws, and it embraces the rim of the hook throughout its periphery except for the gap between the loop-seizing beak I6 and the loop-controlling tail I'I. Three laterally extending legs 30 are provided each of which carry an L-shaped fan-blade 3l, the free limbs of which extend into the chamber and towards the hub of the hook.

From the foregoing it will be observed that each of the fan-blades is arranged so that the portion which will travel at the greatest speed is xed to the hook-body. As rotary hooks attain a speed of 10,000 R. P. M. this is a highly advantageous feature. It will be obvious that as the fan-blades are made of sheet metal the free ends of the blades may be turned to anyl desired angle relative to their axis of rotation so that, instead of acting asa centrifugal fan as illustrated, the ian blades may act to blow air directly upon the hook.

Having thus set forth the nature of the invention what I claim herein is:

1. A rotary hook for sewing machines comprising a cup-shaped body formed with a rim portion and a centrally located hub, the rim portion being formed with a. loop-seizing beak and a gap adjacent said beak, a guard-plate secured to the outer periphery of the rim portion and fan-blades carried by said guard-plate.

2. A rotary hook for sewing machines comprising a cup-shaped body formed with a rim portion and a centrally located hub, the rim portion being formed with a loop-seizing beak and a gap ad- Jacent said beak, a guard-plate secured to the outer periphery of the rim portion and formed with a laterally extending leg, and an L-shared fan-blade carried by said leg, one limb of the fan-blade'being secured to the leg and the free limb extending inwardly towards the hub.

n 3. A rotary hook for sewing machines comprising a body having an axial hub, radial arms carried by and extending outwardly from said hub, a laterally extending arm iixed to the free end of each of the radially extending arms, said laterally extending arms being arranged parallel to and spaced from and overhanging said hub, thereby forming an air space between said arms and hub, a rim carried by the laterally extending arms and formed with a loop seizing beak and a thread-'case raceway, and a fan blade mounted at one end cna part of said hook-body remote vfrom said hub and extending inwardly into said air space and terminating at its free end adjacent said hub.

JOHN D. KARLE. 

